The contents of Japanese Patent Application No. 9-248556, with a filing date of Sep. 12, 1997 in Japan, and of Japanese Patent Application No. 9-342905, with a filing date of Dec. 12, 1997 in Japan are hereby incorporated by reference.
1. Field of the Invention
This invention relates to improvements in a carpet material for a variety of carpets, and more particularly to a carpet material which is improved in acoustic performance such as sound absorbing and insulating performances and suitable for use as a carpet for an automotive vehicle.
2. Description of the Prior Art
A conventional carpet material for a carpet is constituted of a base section formed of nonwoven fabric. The nonwoven fabric base section has a pile layer designed to form cord-tone pattern, dilour-tone pattern or the like for the decorative purpose of the surface of the nonwoven fabric base section. The nonwoven fabric section has a lower impregnated layer which is impregnated with latex for the purpose of fixing the pile layer. Such a conventional carpet material is disclosed in Japanese Patent Provisional Publication Nos. 52-53980 and 61-132667. Additionally, similar carpet materials have been proposed for carpets of automotive vehicles, as disclosed in Japanese Patent Provisional Publication Nos. 56-140175, 57-205251 and 59-204982. In such carpet materials, a backing layer is laminated to a lower impregnated layer of a nonwoven fabric base section like that discussed above, thereby forming a laminated structure. The backing layer is a sheet formed of polypropylene or polyamide, or a thermoplastic sheet formed of ethylne-vinyl acetate copolymer (EVA) or the like containing inorganic material such as calcium carbonate. Furthermore, a carpet material produced by using no latex has been proposed in Japanese Patent Provisional Publication No. 8-296165 (Japanese Patent Application No. 7-99125), in which each of a pile layer and a base fabric layer is mixed with the same amount of thermally melting fiber of a so-called core-and-clad structure to fix fibers in the layer.
However, the conventional carpet materials are mainly required to have performances of providing design characteristics and wear resistance. Accordingly, the conventional carpet materials have not been required to have acoustical performances such as sound absorbing and insulating performances. However, in recent years, reduction of noise within an automotive vehicle passenger compartment has been required as a part of commercial values, so that acoustic performance has been required for automotive interior materials.
The present invention has been achieved in view of the above and to be intended to provide acoustic performance such as sound absorbing and insulating performances (which have not been required for conventional usual carpet materials) to carpet materials for a variety of carpets to be used in home and in automotive vehicles.
Therefore, an object of the present invention is to provide an improved carpet material for a carpet, which can overcome drawbacks encountered in conventional carpet materials for carpets.
Another object of the present invention is to provide an improved carpet material for a carpet, which can largely contribute to silence in a room provided with the carpet.
A further object of the present invention is to provide an improved carpet material for a carpet, which is high in acoustic performance particularly in a low frequency range.
A still further object of the present invention is to provide an improved carpet material for a floor carpet, which can largely contribute to noise reduction in a passenger compartment of an automotive vehicle provided with the carpet.
A still further object of the present invention is to provide an improved carpet material for a carpet, which is wholly formed of nonwoven fabric.
A first aspect of the present invention resides in a carpet material comprising a pile layer formed of nonwoven fabric and serving as a skin. A base fabric layer is provided for supporting the pile layer and is formed of nonwoven fabric and integral with the pile layer. A backing layer is located at the opposite side of the base fabric with respect to the pile layer, the backing layer being formed of nonwoven fabric and integral with the base fabric layer. Additionally, the nonwoven fabric forming the backing layer has a surface density ranging from 100 to 1000 g/m2 and is formed of polyester-based fiber having a diameter ranging from 20 to 130 xcexcm.
A second aspect of the present invention resides in a floor carpet for an automotive vehicle, formed of a carpet material. The carpet material comprises a pile layer formed of nonwoven fabric and serving as a skin. A base fabric layer is provided for supporting the pile layer and is formed of nonwoven fabric and integral with the pile layer. A backing layer is located at the opposite side of the base fabric with respect to the pile layer, the backing layer being formed of nonwoven fabric and integral with the base fabric layer. Additionally, the nonwoven fabric forming the backing layer has a surface density ranging from 100 to 1000 g/m2 and is formed of polyester-based fiber having a diameter ranging from 20 to 130 xcexcm.
A third aspect of the present invention resides in a floor carpet for an automotive vehicle, the floor carpet being formed of a carpet material. The carpet material comprises a pile layer formed of nonwoven fabric which is formed of polyester-based fiber and serving as a skin. A base fabric layer is provided for supporting the pile layer and is formed of nonwoven fabric and integral with the pile layer, the nonwoven fabric being formed of polyester-based fiber. A backing layer is located at the opposite side of the base fabric with respect to the pile layer, the backing layer being formed of nonwoven fabric and integral with the base fabric layer, the nonwoven fabric being formed of polyester-based fiber. Additionally, the backing layer has a rate of thickness ranging from 10 to 50% relative to a whole thickness of the carpet material, and a storage elastic modulus (log Exe2x80x2) in a dynamic viscoelasticity test, ranging from 5 to 10 Pa within a measuring temperature range of from 0 to 50xc2x0 C. Further, the nonwoven fabric forming the backing layer has a surface density ranging from 100 to 1000 g/m2 and is formed of polyester-based fiber having a diameter ranging from 20 to 130 xcexcm. Furthermore, the nonwoven fabric forming the backing layer is formed of a mixture of polyester-based staple fiber having a diameter ranging from 20 to 130 xcexcm, and binder fiber in an amount ranging from 20 to 80% by weight. The binder fiber is of a core-and-clad type conjugate structure and has a core formed of polyester, and a clad formed of low melting point copolyester having a melting point ranging from 110 to 180xc2x0 C.
A fourth aspect of the present invention resides in a method of producing a carpet material, comprising the following steps: (a) forming a first nonwoven fabric constituting at least a pile layer; (b) forming a second nonwoven fabric constituting at least a backing layer; (c) laminating the second nonwoven fabric on the first nonwoven fabric to form a laminated structure; and (d) accomplishing a needle punch treatment onto the laminated structure so as to make needle punching in a direction of from the second nonwoven fabric to the first nonwoven fabric by a needle punch device, in which a part of the first woven fabric is pushed out downward to form the pile layer and simultaneously to make integral the pile layer and the backing layer with each other.
A fifth aspect of the present invention resides in a method of producing a carpet material, comprising the following steps: (a) forming a first nonwoven fabric constituting a pile layer and a base fabric layer under a needle punch treatment; (b) forming a second nonwoven fabric constituting a backing layer by using a card layer type nonwoven fabric producing device; (c) laminating the second nonwoven fabric on the first nonwoven fabric to form a laminated structure; and (d) accomplishing a needle punch treatment onto the laminated structure so as to make needle punching in a direction of from the second nonwoven fabric to the first nonwoven fabric by a needle punch device, in which a part of the first woven fabric is pushed out downward to form the pile layer and simultaneously to make integral the pile layer, the base fabric layer and the backing layer with each other.
A sixth aspect of the present invention resides in a method of producing a carpet material, comprising the following steps: (a) forming a first nonwoven fabric constituting a pile layer, and a second nonwoven fabric constituting a base fabric layer and a backing layer, by a card layer type nonwoven fabric producing device on a single production line, the second nonwoven fabric having a surface density which is 1.5 to 5 times of that of the first nonwoven fabric; (b) laminating the second nonwoven fabric on the first nonwoven fabric to form a laminated structure; and (c) accomplishing a needle punch treatment onto the laminated structure so as to make needle punching in a direction of from the second nonwoven fabric to the first nonwoven fabric by a needle punch device, in which a part of the first woven fabric is pushed out downward to form the pile layer, while a part of the second woven fabric is tightened by an upwardly bent portion of each needle of the needle punch device so as to form a high density section serving as the backing layer.
According to the present invention, the carpet material can provide excellent sound insulating and absorbing performances throughout a wide frequency region including the low frequency range and the high frequency range, while fulfilling the inherently required conditions as a carpet material. The carpet material of the present invention is very effective in sound insulating performance particularly in the low frequency range, which is important for a carpet to be used in a passenger compartment in an automotive vehicle.